Process for producing a solid rinse block



Sept. 13, 1966 J. DIAMOND ETAL 3,272,899

PROCESS FOR PRODUCING A SOLID RINSE BLOCK Original Filed Dec. 6, 1960INVENTORS. JACK DIAMOND BY MY/VE M. GAU/VTT A TTORNE).

United States Patent 3,272,899 PROCESS FOR PRODUCING A SOLID RINSE BLUCKJack Diamond, Culver City, and Wayne M. Gauntt, Los

Angeles, Calif., assignors to Hagan Chemicals & Controls, Inc,Pittsburgh, Pa.

Original application Dec. 6, 1960, Ser. No. 74,178, now Patent No.3,154,498, dated Get. 27, I964. Divided and this application Apr. 3,1964, Ser. No. 362,546

5 Claims. (Cl. 264-426) This is a division of our copending patentapplication, S.N. 74,178 filed December 6, 1960, now Patent No.3,154,498, which is a continuation-in-part of our copending patentapplication Serial No. 854,341 filed November 20, 1959 now abandoned,the entire specification and claims of which are adopted herein as partof this disclosure and the benefit of the filing date for which isclaimed.

This invention relates particularly to the treament of rinse water usedin dishwashing machines and the like. It may be utilized in generalwhenever it is desired to lower the surface tension of water.

Prior to the present invention, it had been a widespread practice incommercial dishwashing operations to inject into the rinse water of thedishwashing machine a more or less regulated amount of a liquid wettingagent. The purpose of the wetting agent is to lower the surface tensionof the rinse water in order to minimize spotting, streaking, and thelike on dishes, glassware, tableware, and other utensils as they dry.Having a lowered surface tension, the water tends to roll off thesurface of the dishes, glasses, or table utensils, carrying with it anyimpurities present. Unsightly depositions on the glassware, tableware,and the like which would otherwise occur on drying of the water dropsare thus prevented.

Such treatment of the rinse water is quite useful to a restaurantoperator for example, because it greatly hastens the drying process. Inaddition, sanitary laws in most localities prohibit the use of towels orother hand drying methods in public eating places. Rinse water treatmentis also desirable for domestic dishwashers, but has not been widelyaccepted largely because of difficulties in dispensing. Rinse watertreatment is desirable in washers used for cleaning any hard surfacematerial such as cans, bottles, metal parts, plastics, etc.

Other uses for wetting agents in general may be mentioned. Among theseare improving the usefulness of irrigation water by insuring itspenetration into the soil, improving the wettahility of fire-fightingwater, and so on.

There are several notable disadvantages to liquid rinse treatingcompositions. Perhaps foremost among them is a difiiculty of controllingthe rate of addition of the composition according to varying needs.Relatively complicated dispensers are needed to insure that the entiredose will not be consumed and drained out of the washer in the first fewseconds of rinsing. In domestic dishwashers where the rinsing operationtakes place in the washing chamber, the dispensers required are much tooelaborate and hence too expensive and may still be subject to breakdown.Consequently, domestic dishwashers are usually not equipped with liquidrinse-aid dispensers.

A further disadvantage to liquid rinse-treating compositions in generalis that the so-called low sudsing wetting agents should comprise atleast part of the composition.

3,272,899 Patented Sept. 13, 1966 They should be used because of theotherwise uncontrolled formation of eificiency-reducing foam due toimmediate dispersion and high solution rates. The low sudsers used inthe liquid rinse treating compositions are not particularly goodcleaners due to their hydrophobichydrophilic balance.

We have invented a new process for producing a product which providesexcellent rinse water without the necessity of complicated metering orinjection devices and which requires a minimum of attention even forreplenishment.

We have discovered that a composition of solid wetting agents may befor-med into a block, pellet or bar and posi- -tioned in the stream ofrinse water to provide a gradual and controlled rate of dissolution,thus adding to the rinse water (or water to 'be used for other purposes)the desired amount of wetting agent, all the while maintaining bettersurface activity than is possible with a liquid rinseaid agent. We mayalso employ a rinse-aid block of our composition which may be situatedloose anywhere in the chamber of a washing machine and which willperform its function without the use of a dispenser of any kind.

In the accompanying drawings, FIGURE 1 shows a block of our invention ofa shape appropriate for a feeder of a particular type.

FIG. 2 shows the block of FIG. 1 positioned in the feeding chamber of afeeder adapted for insertion into the rinse water line of a commercialdishwasher.

FIG. 3 illustrates a presently preferred form of a packet designedespecially for use in domestic dishwashers.

Referring to FIG. 1, the block is of cylindrical shape. The blockconsists essentially of one or more solid wetting or surface-activeagents and whatever other ingredients may appear desirable, althoughnone need be used. The preferred chemical compositions and methods ofmanufacture will be discussed infra. Of course, the block may be inother forms such as cubical or conical. Where paper cups are used asmolds, the blocks will be in the form of tapered cylinders.

In FIG. 2 a purely illustrative rinse-aid feeder is shown loaded with ablock of our invention. Chamber 1 defined by housing 3 is sealed at thetop by cap 2. Within the chamber 1 are a weight 4, weight carrier 5, anda block of our rinse additive 6. The block of rinse additive rests on awire screen 7 or other suitable screen of medium mesh. Water passingthrough pipe 8 enters chamber 9 and contacts the block of rinse additivethrough screen 7. In so conducting the block, the water dissolves asmall portion of the block and passes out through pipe 10 to be used. Afeeder capable of exposing a controlled area to the water may be usedwhere a higher degree of control over the rate of consumption isdesired; however, such a feeder need not be used in our invention. Anexample of such a feeder, designed to expose only an end surface of acylindrical block, would be a feeder similar to that of FIG. 2, in whichthe diameter of chamber 1 is equal to the diameter of the cylindricalrinse-aid block. The illustrated feeder may be used without the weightor weight carrier and without regard to the diameter of the block inrelation to the diameter of the feeder where a controlled exposedsurface area is not critical.

In FIG. 3 a packet of rinse-aid material of our invention is depicted.It is designed particularly for use in domestic dishwashers. Itcomprises an envelope 20 of mesh material or having perforations,enclosing a block or pellet 21 of our rinse-aid material. Envelope 20may be made of a soluble material such as a polyvinyl alcohol or aninsoluble one. Our preferred domestic product is enclosed in an envelopeof insoluble mesh material. If a soluble material is used for theenvelope, it may be designed to dissolve during the wash cycle of thedishwasher so that the rinse-aid material is not exposed to the Wateruntil the rinse cycle begins. Where this result is desired, theenvelope, of course, need not be in the mesh form, but may be solid.Moreover, it may be in the form of a simple coating on the block orpellet. The block or pellet 211 may be of any shape. It should be notedthat a relatively thin disc combines the characteristics of constantrate of solution (relatively constant surface area throughout life) withease of manufacture.

Several factors must be considered in the proper use of our invention.In addition to the methods discussed above of exposing the block to thewater, a very effective method of exposing the block to water is merelyto insert it directly in the pipe or stream of water feeding the rinsewater. In domestic dishwashers and so-called underthe-counterdishwashers, the block may be deposited anywhere in the washing chamber.Or, depending on the rate of solution desired, more or less surface areamay be exposed in one way or another to the water. In addition to thefactors mentioned above on the subject of exposure to water, it shouldbe said that too great a downward force (provided by weight 4) on theblock resting on a screen as in FIG. 2 may extrude the rinse-aid andcause undesirable deposits of solid material. The water pressure is alsosignificant. Temperature of the water also affects the solubility underthe circumstances. We have found that the solid wetting agents are notas soluble in cold water as in hot Water. Thus, a relatively solubleagent should be used for fire-fighting applications, for example.

Another factor affecting our invention is the composi-- tion of therinse-aid block. Generally, any wetting agent in pellet, block, or barform is within the contemplated area of our invention. However, we havefound that some wetting agents perform better in our invention when theyare in the presence of other materials to be described infra.

Another factor which significantly affects the performance of ourinvention is the method of manufacture of the block or pellet in itsfinal form. This, too, will be taken up infra.

COMPOSITION Although any solid wetting agent is contemplated in ourinvention, we have found that certain solid compositions are better thanothers. We have also found that the inclusion of a small amount of along chain substituted amide will assure proper control over thesolution rate of the composition in the range of temperatures normallyused in hot water mechanical washers. Specifically, we may include inour rinse-aid block solid nonionic wetting agents of the type known asPluronic F-68, Tetronic 707 or 908, Triton X-67, any of the Carbowaxseries, and Igepal DJ-970. The chemical compositions presently soldunder these trademarks are as follows:

(1) Pluronic F68A solid ethylene oxide-propylene oxide block polymer:

| no (CHzCHzO) (CHzCHO)b(CHzCH20) cH inwhich a. and c are about 82 and bis about 31.

(7) Igepal DJ970A solid alkyl phenoxy poly (ethyleneoxy) ethanol.

Among the alkyl substituted amides which we may use are Acrawax (GlycoProducts Company), Armowax (Armour), and Armid HT (Armour). Armowax, ourpreferred composition, is a commercial form of methyldistearyldiamide:

amil O CH:

Armid HT is a commercial form of stearamide:

H35C17(INHZ We may use any normally solid waxy amide having the generalformula:

0 X Mini-Y where R is an alkyl group of at least about 6 carbon atoms; Xis H or an alkyl group; Y is H, alkyl group, or a group having theformula where n is an integer from 1 to about 4, Z is an alkyl grouphaving at least about 6 carbon atoms, and Q is hydrogen or an alkylgroup.

Although a great many variations in combinations of the describedingredients and others may be made according to this invention, we havefound a particular range of constituents to be the best performers inmechanical dishwashers. The relative performance of various compositionsis in many respects a matter of judgment based on visual observation ofthe degree of spotting, streaking, fogging, and the like. It should berecognized, however, that the advantages of ease in handling anddispensing are obtained in each case.

One method of measuring the effectiveness of a wetting agent is toobserve the change in surface tension of the treated water brought aboutby the additive. To this end, the following test was run. A group ofblocks were made as follows, by weight: 4 /2% Armowax, 23%% Pluronic F-68, 721% Tetronic 908, melted together at 300 F., poured into cylindricalplexiglass 1%" internal diameter molds, and immediately placed in arefrigerator at 30 F. to solidify. The test included preparation of fourtest solutions of one liter each by dissolving the desired amount ofrinse additive composition in water at 195 F. and adding it to the litercontainer. The water in each solution prior to addition of the rinseadditive had a surface tension at room temperature of 73 dynes persquare centimeter by the DuNouy method. Table I compares results in thefour solutions at various temperatures:

Table I.-Surface tension (dyn'eS/sq. cm.)

Another test was run to demonstrate the solubilities of compositions ofvarying amide content. To this end, rinse-aid blocks weighing 50 gramseach were molded in standard laboratory test tubes. They contained thefollowing ingredients:

(No. 1) 5% Armowax, 20% Pluronic F-6 8, 75% Tetronic 908 (No. 2) 10%Armowax, 20% Pluronic F-68, 70% Tetronic 908 (No. 3) Armowax, PluronicE68, 65% Tetronic 908 (No. 4) 20% Armowax, 20% Pluronic F-68, 60%Tetronic 908 The rinse-aid sticks were used in a complete washn'nse-drycycle of a standard domestic dishwasher using tap water at 120 F. Theaverage weight losses in grams ranged progressively from 1.8 g. to 0.80g. for composi' tions 1 thru 4. A composition even more soluble thancomposition No. 1 is that consisting of 3.5% Armowax, 21.5% PluronicF-68, and 75 Tetronic 908.

In general our rinse-aid block may consist of any solid nonionic wettingagent which may be formed in a block, pellet, or bar. The softeningpoint of the finished mixture should not be significantly lower thanwater temperatures usually encountered in the normal contemplated use ofthe block, although any individual ingredient may have a melting pointlower than this range.

MANUFACTURE The method followed in manufacturing the rinse-aid blockdefinitely affects its performance. The procedure will be discussed stepby step.

A. The powdered or chunk wetting agents, if more than one are used, arein the preferred procedure first mixed in dry form. Next the wettingagent materials are melted together under gentle agitation and thesubstituted amide is preferably added after the wetting agents have atleast begun to melt. The agitation used should not be of the type whichis likely to cause bubbling or air entrapment. In the case of ourpresently preferred dish rinse composition consisting of 72% Tetronic908, 23 /2 Pluronic F-68, and 4 /2% Armowax, the temperature of the meltneed not exceed 150 C. At about 145 C., a homogenous liquid has beenformed.

B. After the material has reached the homogenous liquid state, one oftwo preferred procedures may be followed. The choice of procedure willdepend primarily on the rate of solution desired and the intended use ofthe product.

Generally, a pro-duct intended for use in a line-type dispenser such asis found in commercial (restaurant) dishwashers should be more solublethan a product intended for use in a domestic or other dishwasher whereit will be placed loose in the washing and rinsing chamber and subjectedto considerable buffeting, forced spray and the like. This is true eventhough the water used in the commercial dishwasher is likely to behotter than that of the domestic dishwasher.

A product of low solubility for use in domestic dishwashers rnay beprepared by pouring the homogenous melt directly into molds of thedesired final form and permitting them to cool slowly. A suitableinexpensive mold is an ordinary paper cup. If a paper cup is used as amold, an additional advantage is obtained in that the product may besold already packaged in its own mold. Of course, the mold may beremoved and the product packaged in any manner seen fit.

On the other hand, a product containing the same chemical ingredientsbut nevertheless having a much higher solubility rate may be prepared bypouring the homogenous liquid melt into flat pans to a depth of about A"to /2" and cooling it by subjecting it immediately to a cold environmentas low as about 0 F. or as high as room temperature.

Our preferred product for commercial dishwashers having line-typedispensers is made by pouring the homogenous liquid melt into flat pansto a thickness of about A" to about V2" and placing the pans on awater-cooled conveyor for about 16 minutes. The water-cooled environmentpreferably is at a temperature of about 50 F.70 F. During thewater-cooling period, the mass achieves a fairly solid state. Aftertln's cooling period, the pans are further air-cooled for about 45minutes.

C. After solidification and cooling of the substance in the pans, it ispreferably chipped or crushed into small pieces and compressed into thedesired final shape. About 5000 p.s.i. is quite sufficient to achievesuperior compactness. Higher pressures up to about 7000 p.s.i. have beentried and also provided excellent results.

The several factors mentioned above which affect the performance of theproduct will be discussed again below:

(1) Time required for melting.-There appears to be no practical effecton solubility caused by the relatively long melting period required forlarge batches of composition as opposed to small batches.

(2) Thickness 0r depth-The depth or thickness of the mass during thecooling period definitely affects the resultant solubility of theproduct. The low thermal conductivity of the materials greatly delayshardening of the innermost portions of the mass, which permits crystalformations of segregated materials and consequent lower over-allsolubility rates. The over-all solubility rate is thus inversely relatedto the thickness of the mass during cooling.

(3) Rate of c00ling.Generally, the more rapidly the melt is cooled, themore rapidly the product will dissolve. The rate of cooling below aboutF., however, does not appear to be critical. A melt poured atapproximately 300 P. will remain substantially unchanged until it coolsto about 250 F. In the range between 250 F. and about 100 F., however,hardening takes place in the form of particle formation. Where the massis cooled through this range slowly (i.e. 45 minutes or more), theproduct will exhibit the characteristic of slow solubility. For example,a 30 gram product poured into a paper cup mold and cooled at roomtemperature will require more than 24 hours to dissolve in a waterpassage. Under the same conditions, a compressed 60 gram briquette madefrom rapidly cooled material requires only about 1 /2 hours tocompletely dissolve.

Rapidly cooled material, such as that placed in a freezer immediatelyafter pouring, develops a clear acteristic fracturing pattern stretchinginwardly from the outer edges of the mass. Conversely, the slowly cooledmaterial exhibits correspondingly fewer fractures. A chilled surface mayexhibit, in addition to the cracks, a wrinkling effect accompanied by araising or expansion of the surface. This is an additional reason whythe direct mold product should not be subjected to cold, but rathershould be cooled slowly. Cooling at an intermediate rate produces aproduct of intermediate solubility.

PERFORMANCE The performance of the product is affected by the factors ofcomposition and manufacturing procedure already discussed. In addition,several other factors should be mentioned.

A. Temperature of the water.-Although we have made no recorded studiesdirected specifically to the effect of temperature of the water onsolubility and performance, from visual observation and studies on otherfactors we have determined that the products of our invention dissolvemore readily in higher temperature water. However, the differencethrough the range of normal hot water temperature (in the home, normally110 F. to 140 F.; in commercial usage, up to about 190 F.) is not greatenough to significantly affect ultimate performance, especially in adomestic dishwasher where the factor of attrition is at least assignificant as the temperature of the water.

B. Particle size of the compressed product.--Very small particles willphysically separate from the block before dissolving.

C. Nonuniformity f s0lubility.A coral-like effect appears on the surfaceof the compressed block during dissolution. This is primarily due to therelatively high solubility of the portions which cooled and solidifiedfirst.

Although we speak of solubility and use the word dissolve in the popularsense throughout the specification, it will be understood by thosefamiliar with the art that the large molecules of the materials used inour invention do not dissolve as does salt or sugar. In using the wordsdissolve, solubility, and the like, we mean to include the process ofdispersion throughout a liquid medium which may or may not beaccompanied by molecular dissociation.

D. Position of the bl0ck.The method of exposing the block to wateraffects the solubility rate also. A dispenser of the type shown in FIG.2 provides a relatively low consumption rate. Even lower consumption maybe achieved by exposing only one surface of the block to the water, asby employing a cylindrical dispenser of the same diameter of the block.Positioning the block directly in the stream of water, as in an enlargedchamber located directly in the pipe line, provides slightly higherconsumption rates.

In an open chamber such as that of a domestic dishwasher, the attritioncaused by butfeting and high pressure sprays results in higherconsumption rates. If the block is partially protected by a small wirebasket or the like, a lower rate of consumption will result. Theinsoluble plastic mesh envelope shown in FIG. 3 prevents excessive ratesof consumption due to attrition and breakage not only by absorbing theforce of the spray but also by holding separated particles within it.

Having thus described and illustrated several presently preferred formsand variations of our invention, it should be distinctly understood thatit may be otherwise various- 1y embodied and practiced within the scopeof the following claims.

We claim:

1. Method of making a solid rinse and block which will dissolvegradually and uniformly comprising:

(a) melting together at least one solid nonionic wetting agent and, inan amount about 3% to about 20% of the total weight of the melt, analkyl substituted amide having the formula r R-d-N-Y where R is an alkylgroup of at least about 6 carbon atoms, X is selected from the groupconsisting of hydrogen and alkyl groups, and Y is selected from thegroup consisting of hydrogen, alkyl group, and radicals of the formula 3i (C Z)n N where n is an integer from 1 to about 4, Z is an alkyl grouphaving at least about 6 carbon atoms, and Q is selected from the groupconsisting of hydrogen and alkyl groups;

(b) pouring the melt thus formed in a shallow pan;

and

(c) cooling the melt in said shallow pan in the temperature range fromabout 0 F. to room temperature, whereby a solidified mass is formed.

2. The method of claim 1 including the steps of dividing the solidifiedmass into particles, and pressing said particles into a desired shape.

3. The method of claim 1 in which the melt is chilled immediately afterpouring into the shallow pan, thereby forming a characteristicfracturing pattern.

4. The method of claim 1 in which the melt is cooled slowly, therebyproducing a solidified product exhibiting few fractures and having aslow solution rate.

5. The method of claim 1 in which the alkyl substituted amide ismethylene distearamide, and the solid nonionic wetting agent comprisessolid alkoxylated ethylene diamine and a solid ethylene oxide-propyleneoxide block polymer, the latter being about 20% to about 27% of theweight of the melt.

References Cited by the Examiner UNITED STATES PATENTS 1,031,227 7/1912Artmann 264157 1,401,050 12/1921 Crouch 264-299 XR 1,416,483 5/1922Loveland 264-212 1,884,529 10/1932 Benner et al 264109 1,970,578 8/1934Schoeller et al. 2,559,583 7/1951 Barker. 2,643,229 6/ 1953 Walters.2,674,619 4/ 1954 Lundsted. 3,059,275 10/1962 Vogt 264126 XR OTHERREFERENCES Callaham, John R.: DDT Fights Insects in War and in Peace, inChemical and Metallurgical Engineering, vol. 51, October 1944, pp.109114.

Wyandotte technical data on: Pluronics for Home and Commercial LaundryFormulations, Jan. 7, 1957, page 3 (Pluronics I).

Wyandotte technical data on: Pluronics in Metal Cleaning Formulations,Jan. 7, 1957, page 9 (Pluronics II).

ALEXANDER H. BRODMERKEL, Primary Examiner.

ALFRED L. LEAVITT, Examiner.

P. E. ANDERSON, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,272,899 September 13, 1966 Jack Diamond et a1,

It is hereby certified that error appears in the above numbered patentrequiring correction and that the said Letters Patent should read ascorrected below.

In the grant, lines 2 and 3, for "assignors to Hagan Chemicals GControls, Inc, of Pittsburgh,Pennsylvania" read assignors to CalgonCorporation, a corporation of Pennsylvania line 12, for "Hagan ChemicalsG Controls, Inc read Calgon Corporation, and in the heading to theprinted specification, lines 5 and 6, for "assignors to Hagan ChemicalsG Controls, Inc, Pittsburgh,Pa,. read m assignors to Calgon Corporation,a corporation of Pennsylvania -o Signed and sealed this 22nd day ofAugust 1967,

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J, BRENNER Attesting Officer Commissioner ofPatents

1. METHOD OF MAKING A SOLID RINSE AND BLOCK WHICH WILL DISOLVE GRADUALLYAND UNIFORMLY COMPRISING: (A) MELTING TOGETHER AT LEAST ONE SOLIDNONIONIC WETTING AGENT AND, IN AN AMOUNT ABOUT 3% TO ABOUT 20% OF THETOTAL WEIGHT OF THE MELT, AN ALKYL SUBSTITUTED AMIDE HAVING THE FORMULA2. THE METHOD OF CLAIM 1 INCLUDING THE STEPS OF DIVIDING THE SOLIDIFIEDMASS INTO PARTICLES, AND PRESSING SAID PARTICLES INTO A DESIRED SHAPE.